One type of magnetic sensor is a Hall-effect sensor (Hall sensor). A Hall effect sensor is a transducer that varies its output voltage (Hall voltage) in response to a magnetic field. It is based on the Hall effect which makes use of the Lorentz force. The Lorentz force deflects moving charges in the presence of a magnetic field which is perpendicular to the current flow through the sensor or Hall plate. Thereby, a Hall plate, referred to as the sensor element, can be a thin piece of semiconductor or metal. The deflection causes a charge separation which causes a Hall electrical field. This electrical field acts on the charge in the opposite direction with regard to the Lorentz Force. Both forces balance each other and create a potential difference perpendicular to the direction of current flow. The potential difference can be measured as a Hall voltage and varies in a linear relationship with the magnetic field for small values. Hall effect sensors can be used, for example, for proximity switching, positioning, speed detection, and current sensing applications.
In Hall sensor readout circuits, the magnetic signal from the Hall sensor element is converted to an electrical signal (e.g., a Hall voltage) which is further amplified and calibrated before reaching an output of the sensor. The Hall voltage may vary over temperature. For example, a non-linear relationship between the Hall voltage and temperature may exist such that as temperature increases, the Hall voltage decreases. This non-linear sensitivity variation over temperature of the Hall should be compensated for accurate sensing measurements.
Typically, in Hall sensor readout circuits, a digital interface is used for low speed operations (e.g., up to 10 kHz). That is, the analog output of the Hall sensor element (e.g., the Hall voltage) is converted into a digital signal by an analog-to-digital converter (ADC). Thus, all the compensations are calculated and implemented in the digital domain and a digital stream of N-bits is output from the readout circuit. This technique does not perform well for high bandwidth operations (e.g., 10 kHz to 120 kHz).
Thus, a magnetic Hall sensor may be desired that is capable of performing at higher speeds, for example, at a bandwidth up to 120 kHz.